Visual indicator with sensor

ABSTRACT

A fluid level gauge includes a housing having a first end and a second end, and a window disposed in the housing, proximate to the first end. The fluid level gauge further includes an optical sensor disposed in the housing, proximate to the second end. A prism is disposed in the housing, between the optical sensor and the window, such that the prism and the window define a fluid chamber therebetween. The housing further includes a plurality of through holes that provides a fluid path from outside the housing to the fluid chamber.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/569,629, filed on Aug. 8, 2012, entitled Visual Indictorwith Sensor, currently pending.

FIELD OF INVENTION

The present disclosure relates to sight glasses. More particularly, thepresent disclosure relates to sight glasses having a visual indicatorand an electro optic sensor for use in a splash lubricated environment,such as a gearbox.

BACKGROUND

A sight glass is a transparent tube through which an operator of a tank,boiler, gear box, or other machine can observe a level of liquid (suchas oil or hydraulic fluid) contained within. A sight glass includesglass or a polymeric material that acts as a reflector when no liquid ispresent. When liquid is in contact with the glass or polymeric material,light passes through the sight glass. Accordingly, the presence ofliquid in the system can be quickly verified. In other known systems,the sight glass is replaced with a sensor.

SUMMARY OF THE INVENTION

In one embodiment, a fluid level gauge includes a housing having a firstend and a second end, and a window disposed in the housing, proximate tothe first end. The fluid level gauge further includes an optical sensorincluding a prism, a light transmitter, and a light receiver disposed inthe housing, proximate to the second end. The optical sensor and thewindow define a fluid chamber therebetween, with the light transmitterand the light receiving being disposed between the prism and the fluidchamber. The housing further includes a plurality of through holes thatprovides a fluid path from outside the housing to the fluid chamber.

In an additional embodiment, a fluid gauge includes a housing having awindow disposed in a first end, and a sensor comprising a prism, a lighttransmitter, and light receiver disposed in a second end, with a fluidchamber disposed between the window and the light transmitter and thelight receiver of the sensor. The housing includes a plurality ofapertures that define a plurality of fluid paths to the fluid chamber.The window provides an unobstructed view of the fluid chamber to anoperator. The window at least partially reflects light when the fluidchamber is empty, and light at least partially passes through the windowwhen fluid is in contact with the window.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings, structures are illustrated that, togetherwith the detailed description provided below, describe exemplaryembodiments of the claimed invention. Like elements are identified withthe same reference numerals. It should be understood that elements shownas a single component may be replaced with multiple components, andelements shown as multiple components may be replaced with a singlecomponent. The drawings are not to scale and the proportion of certainelements may be exaggerated for the purpose of illustration.

FIG. 1 is a side view of one embodiment of a fluid level gauge;

FIG. 2 is a front view of the fluid level gauge;

FIG. 3 is a cross-section of the fluid level gauge;

FIG. 4 is a front view of one embodiment of a light shield;

FIG. 5 is a perspective view of another embodiment of a fluid levelgauge; and

FIG. 6 is a cross-section of the fluid level gauge of FIG. 5.

DETAILED DESCRIPTION

FIG. 1 illustrates a side view of one embodiment of a fluid level gauge100. The fluid level gauge 100 may also be referred to as a liquid levelgauge or a fluid gauge. The fluid level gauge 100 includes a housing 110having a first end 120 and a second end 130, and a window 140 disposedin the housing 110, proximate to the first end 120.

The fluid level gauge 100 is configured to be placed in a fluidreservoir (not shown), such as a fluid tank in a vehicle or othermachine, or a standalone fluid tank. The placement of the fluid gauge100 is such that the first end 120 of the housing 110 extends outside ofthe reservoir, so that the window 140 may be viewed by an operator. Thesecond end 130 of the housing is inside the machine and in contact withthe fluid.

In the illustrated embodiment, the housing 110 includes a hexagonalportion, and several cylindrical portions of different diameters.However, it should be understood that the housing may take any shapethat may be practical.

The fluid level gauge 100 further includes a pod 150 that is connectedto the housing 110 by a cable 160. The pod 150 may include electronics(not shown), such as a processor, and a power source (not shown), suchas a battery. The pod 150 may further include a connector, cables, orwires (not shown) to interface with a machine, such as a vehicle,computer, or any other external device. The pod may include an indicator170 that conveys information to an operator. Exemplary indicatorsinclude, without limitation, light emitting diodes, incandescent lights,an LCD display, and a touch screen, a pop out indicator, or otherelectro-mechanical, non-volatile device. However, it should beunderstood that any electro-mechanical indicator, or other indicator maybe used. It may be preferable to position the indicator at an accessiblelocation.

FIG. 2 illustrates a front view of the fluid level gauge 100. As can beseen from this view, the window 140 may include a plurality ofconcentric circles 210. In one embodiment, the concentric circles areformed by ridges disposed on the window. In an alternative embodiment,the concentric circles 210 are etched into the window 140. In analternative embodiment, the concentric circles are painted or otherwiseadhered to the window 140.

The window 140 may also be referred to as a “sight glass” due to itsfunction as a visual inspector and visual indicator of a fluid level.Although the window 140 may be referred to as a sight glass, it shouldbe understood that the window 140 need not be constructed of glass, butmay be constructed of a polymeric material. The window 140 at leastpartially reflects light when it is surrounded by air. However, whenfluid is in contact with the window 140, the window 140 allows at leasta portion of light to pass through. The window may be configured, suchthat when the fluid is at a minimum fluid level, light passes through atleast a portion of the window 140. At any given fluid level, light thatpasses through the fluid at least partially passes through the window140, and light that travels above the fluid is at least partiallyreflected by the window 140. In one embodiment, the window may be aFresnel lens.

FIG. 3 illustrates a cross-section of the fluid level gauge 100. As canbe seen from this view, the fluid level gauge 100 further includes anoptical sensor including a light transmitter 305, a light receiver 310,and a prism 320 disposed in the housing 110, proximate to the second end130 of the housing 110. In the illustrated embodiment, the sensor is insignal communication with a printed circuit board 315. The sensors mayinclude infrared photosensors, photodiodes, phototransistors, or anyphotosensitive component. It should be understood that any light sourceand photosensing component may be used.

In the fluid level gauge 100, the prism 320 of the optical sensor isdisposed in the housing 110, such that the prism 320 and the window 140define a fluid chamber 325 therebetween. In one embodiment, the prism isconstructed of a polymeric material. In other embodiments, the prism maybe constructed of glass, fused silica (quartz), or other lighttransmitting material. In an alternative embodiment, the prism may beomitted and the device may instead employ one or more reflectivesurfaces to define one or more light paths.

The housing 110 further includes a plurality of through holes 330 thatprovides a fluid path from outside the housing to the fluid chamber 325.As can be seen in the illustrated embodiment, the window 140 provides anunobstructed view of the fluid chamber 325 to an operator. In theillustrated embodiment, the window 140 includes a plurality of ridgesthat define the concentric circles 210 that are visible to the operator.The ridges increase the contrast of visual indication by further bendinglight. In an alternative embodiment (not shown), the window may be flat.As one of ordinary skill would understand, the ridges may be more usefulin instances where the fluid is similar in color to the window, or wherethe light must travel a relatively long distance.

A light shield 335 is disposed in the fluid chamber 325 between theprism 320 and the window 140, thereby defining a first fluid chamber 325a and a second fluid chamber 325 b. In an alternative embodiment (notshown), a plurality of light shields are employed. In anotheralternative embodiment (not shown), the light shield is omittedentirely.

FIG. 4 illustrates a front view of the light shield 335. The features ofthe light shield 335 are described with reference to both FIGS. 3 and 4.The light shield 335 includes a plurality of apertures 340 that allowfluid to flow between the first fluid chamber 325 a and the second fluidchamber 325 b. While twelve apertures 340 are shown in the illustratedembodiment, it should be understood that any number of apertures may beemployed. The apertures may be any shape. In an alternative embodiment(not shown), the light shield is a solid component without anyapertures.

The light shield 335 includes a first side 345 a that faces the prism320, and a second side 345 b that faces the window 140. In oneembodiment, the first side 345 a is formed of an infrared lightabsorbing material, including, without limitation, infrared absorbentpaint, or an absolute black coating. The second side 345 b may or maynot need to absorb infrared light. It may be reflective. Accordingly,the second side 345 b may be constructed of metal, such as aluminum orsteel, or a polymeric material. However, it should be understood thatthe second side may be the same material as the first side. In analternative embodiment, neither side is formed of an infrared lightabsorbing material.

With reference back to FIG. 3, the plurality of through holes 330includes a first through hole 330 a that provides a fluid path to thefirst fluid chamber 325 a, and a second through hole 330 b that providesa fluid path to the second fluid chamber 325 b. In an alternativeembodiment (not shown), the through holes only provide an external fluidpath to one of the fluid chambers, and fluid passes between the firstand second chamber via internal apertures.

The housing 110 also includes a bore 350 extending from the first end120 to the second end 130. Wires 355 extend from the printed circuitboard 310 through the bore 350 to the first end 120 of the housing 110.The wires may further extend through the cable 160 to the pod 150 andthe indicator 170 or a connector or interface.

In operation, light is transmitted from the light transmitter 305, intothe base of the prism 320. When fluid is not present in the fluidchamber 325, the presence of air causes the light to be internallyreflected within the prism. Accordingly, light is reflected back to thelight receiver 310. When the light is received by the light receiver310, the printed circuit board 315 transmits a signal through the wires355 to the pod 160, which provides an indication that the fluid level islow. It should be understood that the sensor may transmit information inthe form of an output voltage via one or more output pins of aconnector.

When fluid is present in the fluid chamber 325, light is transmittedthrough the prism and does not reach the light receiver 310. The pod 160then indicates that the fluid level is acceptable.

A cover 360 is disposed on the second end 130 of the housing 110,covering the sensor components 305, 315, 320. The cover 360 prevents thesensor components 305, 310, 320 from being directly exposed to thefluid. The cover 360 may be transparent, translucent, or opaque.

In the illustrated embodiment, the prism 320 is affixed to the housing110 by a first snap-on ring 365 a and a first sealing o-ring 370 a. Thewindow 140 is affixed to the housing 110 by a second snap-on ring 365 band a second sealing o-ring 370 b. The light shield 335 is affixed tothe housing 110 by a third snap-on ring 365 c. However it should beunderstood that any means may be employed to affix the components to theinterior of the housing.

In another embodiment, the fluid level gauge 100 may include a prism 320that is disposed about its second end 130 and is in direct contact withthe fluid, as shown in FIG. 5, rather than disposed within the housing110, as described above. FIG. 6 is a cross-section view of the fluidlevel gauge 100 of FIG. 5.

As can be seen from FIG. 5, the fluid level gauge 100 includes anoptical sensor that includes, in addition to the prism 320, a lighttransmitter 305 and a light receiver 310 disposed in the housing 110,proximate to the second end 130 of the housing 110. In the illustratedembodiment, the sensor is in signal communication with a printed circuitboard 315. The sensors may include infrared photosensors, photodiodes,phototransistors, or any photosensitive component. It should beunderstood that any light source and photosensing component may be used.

In the fluid level gauge 100, the optical sensor is disposed such thatthe sensor components and the window 140 define a fluid chamber 325therebetween. The housing 110 further includes a plurality of throughholes 330 that provide a fluid path from outside the housing to thefluid chamber 325. As can be seen in the illustrated embodiment, thewindow 140 provides an unobstructed view of the fluid chamber 325 to anoperator. In the illustrated embodiment, the window 140 includes aplurality of ridges that define the concentric circles 210 that arevisible to the operator. The ridges increase the contrast of visualindication by further bending light. In an alternative embodiment (notshown), the window may be flat. As one of ordinary skill wouldunderstand, the ridges may be more useful in instances where the fluidis similar in color to the window, or where the light must travel arelatively long distance.

A cover 360 is disposed on the second end 130 of the housing 110,covering the sensor components 305, 315. The cover 360 prevents thesensor components 305, 310 from being directly exposed to the fluid. Thecover 360 may be transparent, translucent, or opaque. In one embodiment,the cover 360 may be made of a metallic material, such as steel oraluminum.

In this embodiment, the fluid level indicator 100 is capable ofdisplaying the presence or absence of fluid in a splash lubricatedenvironment. For example, while at rest or at a steady stage, anoperator may use the visual indicator, or window 140, to determine thefluid level within the gauge 100. In addition, because the prism 320 isimmersed in fluid, the proper fluid level may be electronicallyindicated.

And, when the gears of the gearbox, for example, are active, thesplashing action of the gearbox is enabled, resulting in fluid dropletscovering the tip of the prism 320. When present on the prism 320, thepresence of the fluid may be electronically sensed. Conversely, if thereis not enough fluid present in the gearbox, the amount of fluid dropletscovering the tip of the prism 320, is reduced and the absence of fluidis electronically indicated.

To the extent that the term “includes” or “including” is used in thespecification or the claims, it is intended to be inclusive in a mannersimilar to the term “comprising” as that term is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “or” is employed (e.g., A or B) it is intended to mean “Aor B or both.” When the applicants intend to indicate “only A or B butnot both” then the term “only A or B but not both” will be employed.Thus, use of the term “or” herein is the inclusive, and not theexclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into”are used in the specification or the claims, it is intended toadditionally mean “on” or “onto.” Furthermore, to the extent the term“connect” is used in the specification or claims, it is intended to meannot only “directly connected to,” but also “indirectly connected to”such as connected through another component or components.

While the present application has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Therefore, the application, in its broaderaspects, is not limited to the specific details, the representativeapparatus and method, and illustrative examples shown and described.Accordingly, departures may be made from such details without departingfrom the spirit or scope of the applicant's general inventive concept.

What is claimed is:
 1. A fluid level gauge comprising: a housing havinga first end and a second end; a window disposed in the housing,proximate to the first end; an optical sensor comprising a prism, alight transmitter, and a light receiver disposed in the housing,proximate to the second end such that the optical sensor and the windowdefine a fluid chamber therebetween, wherein the light transmitter andthe light receiver are disposed between the prism and the fluid chamber;and wherein the housing further includes a plurality of through holesthat provides a fluid path from outside the housing to the fluidchamber.
 2. The fluid level gauge of claim 1, wherein the windowprovides an unobstructed view of the fluid chamber to an operator. 3.The fluid level gauge of claim 1, wherein the optical sensor furthercomprises a printed circuit board.
 4. The fluid level gauge of claim 3,wherein the housing includes a bore extending from the first end to thesecond end, and wherein wires extend from the printed circuit boardthrough the bore to the first end of the housing and to an indicator. 5.The fluid level gauge of claim 1, further comprising a cover disposed onthe second end of the housing.
 6. The fluid level gauge of claim 1,wherein at least a portion of the prism is disposed outside the housing.7. A fluid gauge comprising: a housing having a window disposed in afirst end, and a sensor comprising a prism, a light transmitter, and alight receiver disposed in a second end, with a fluid chamber disposedbetween the window and the sensor, wherein the housing includes aplurality of apertures that define a plurality of fluid paths to thefluid chamber and wherein the light transmitter and the light receiverare disposed between the prism and the fluid chamber, wherein the windowprovides an unobstructed view of the fluid chamber to an operator, andwherein the window at least partially reflects light when the fluidchamber is empty, and light at least partially passes through the windowwhen fluid is in contact with the window.
 8. The fluid level gauge ofclaim 7, wherein at least a portion of the prism is disposed outside thehousing.
 9. The fluid gauge of claim 7, wherein the window isconstructed of a material selected from the group consisting of glassand a polymeric material.
 10. The fluid gauge of claim 7, wherein thesensor is in signal communication with an indicator selected from thegroup consisting of a light emitting diode, an incandescent light, and aliquid crystal display.
 11. The fluid gauge of claim 7, wherein thewindow includes a plurality of visible concentric circles that can beeither molded into the window or printed thereon.
 12. The fluid gauge ofclaim 7, wherein the window has a flat outer surface and a flat innersurface.
 13. A liquid level indicator comprising: a hollow housingdefining a liquid chamber, the housing having a plurality of aperturesdefining a liquid path to the liquid chamber; a window disposedproximate to a first end of the hollow housing; and an optical sensorcomprising a prism, a light transmitter, and a light receiver disposedproximate to the second end of the hollowing housing; wherein the lighttransmitter and the light receiver are disposed between the prism andthe liquid chamber.
 14. The liquid level indicator of claim 13, whereinthe window at least partially reflects light when the liquid chamber isempty, and light at least partially passes through the window whenliquid is present in the liquid chamber and in contact with the window.15. The liquid level indicator of claim 13, further comprising a sealadjacent the window.
 16. The fluid level gauge of claim 13, wherein atleast a portion of the prism is disposed outside the housing.